Item #: SCP-553
Object Class: Safe/Euclid
Special Containment Procedures: SCP-553 itself cannot be contained, because it does not exist within the tangible world in any known dimensions. However, SCP-553 will not leave its "host" (who will be referred to from here on as "host" or "the host") for as long as the host remains living.
The host is required to live on-site at Sector-19, and is not permitted in the vicinity of any SCP objects, regardless of rank or clearance before SCP-553's attachment. This is due to the risk of SCP-553 attaching itself to an indestructable object and causing potential mental distress to the object. Host is to be employed performing custodial duties and menial tasks for the Foundation when not being studied.
Description: SCP-553 does not have any tangible form in any known dimensions; however, various hosts have described it as a "long, weird fish", with Dr. ███████ describing it as "some type of remora". SCP-553 is completely undetectable to anybody but its current host.
When SCP-553 attaches itself to a host, hosts have reported that it swims around their head, sometimes staring at or "sucking" on the host. Hosts report that this sucking is slightly painful and extremely irritating, and will leave a red mark on the host's skin wherever they claim the object is attached.
Hosts have been observed frequently swatting at air, and sometimes self-mutilating. When asked about this behavior, they claim to be trying to "get the damn thing off [them]".
Addendum: SCP-553 came into the foundation's possession attached to Class-D personnel ███ ██████ (D-156162). During his standard psychological evaluation, Dr. ███████ noticed multiple wounds on D-156162's skin, looking similar to claw or nail marks. When pressed about these, D-156162 told Dr. ███████ about a "motherfucking fish, flying around and sucking on [his] skin all the damn time." When Dr. ███████ told him there was no fish around him, and that he was clearly hallucinating, D-156162 became visibly enraged and tried to strangle Dr. ███████, and was terminated by an attending guard. Shortly after this, Dr. ███████ confessed to the guard that she could see SCP-553, describing it in great detail, at which point she was taken in for study.
When Dr. ███████ was studied, she was determined to be hallucinating and insane, and the decision was made to terminate her rather than modify her memory and release her. Agent █████, who carried out the termination order, became the next host, at which point the foundation acknowledged the existance of the remora and classified it as SCP-553.
Studies on various hosts have shown that SCP-553 puts its hosts under a great deal of stress by its actions, and as it is undetectable to anyone else, they eventually suffer a mental breakdown, believing themselves to be hallucinating, often trying to attack the object or cut it off of their skin, and assaulting any person trying to stop or restrain them.
███ █████, the current host of SCP-553, has shown fewer signs of mental deterioration relative to previous hosts, owing perhaps to general staff knowledge of SCP-553's existance and ███'s status as the object's host. For containment reasons, ███ is to be given only a light workload, and is permitted 2 days off per week. Any staff found to be harassing ███ about SCP-553's existance is to be properly disciplined.
No further testing is scheduled, save for ███'s prolonged exposure to SCP-553.